This introductory section is to adult initiation (RCIA 36-251) as the GIRM is to the Roman Missal. The Church gives the background in liturgical and sacramental theology that underpins the sacraments of adult initiation:

Remember, there is no such thing as RCIC. Part II treats how children of catechetical age are initiated. The process is structured like that of adults, but with key adaptations. The document gives an introductory section to address various issues of ministry and liturgy:

This section treats the situation when a baptized non-Catholic wants to join the Roman Catholic Church. First, there is a more general introduction to this section (RCIA 400-410), which gives us the broad view of the issues.

New to Catholicism? I don’t recommend books for Catholics-to-be. I think the best course is to find a good sponsor to be with you all the way through. Failing that, make two or three close friends–people who you naturally trust and hang out with them as they go about their volunteer work in the parish. For new Christians and even Christians who want to be Catholic, I would opt for learn-by-doing, rather than ready and study. I also suggest visiting monasteries and, in a pinch, different Catholics churches, and praying there.